[Proj] Equations for graduated equidistant cylindrical
mikeo2106 at msn.com
Mon Aug 20 09:14:19 EDT 2007
This may not be worded in the most customary way.
The origin of map co-ordinates is the intersection of the equator with the
west edge of the map.
"Lon" means longitude in degrees east from the west edge of the map.
"Lat" means latitude, positive or negative, in degrees.
X is a function only of Lon.
Y is a function only of Lat.
X(Long) = R*Lon*(pi/180).
Each latitude band is bounded by two consecutive parallels of the uniform
Y(0) = 0
Within any latitude band bounded by Lat1 and Lat2, where |Lat2| > |Lat1|,
Y(Lat) = Y(Lat1) + R*(Lat - Lat1)*(pi/180)*sqr(sec(Lat1)*sec(Lat2)).
Projections, including graduated equidistant cylindrical, can be defined
completely by a verbal description in ordinary English, but I was asked for
equations for the graduated equidistant cylindrical.
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